As is well known to those versed in plant husbandry, high costs, as in the labor of repeated transplanting as plants grow, and for the required materials and supplies involved in repeated transplanting, and the rapid wear and deterioration of such supplies, has become oppressive, particularly to the commercial grower. Certain improvements toward reducing labor and materials costs have been made by my prior U.S. Pat. No. 3,846,936. However, there remains the need for additional reductions in labor and material costs.